Question

我有一个DropDownList控件，其中填充了SqlDataSource中的List列表。 SqlDataSource QueryBuilder从我的数据库表中选择Column_Names。

如果DropDownList提供了DataTextField =＆＃34; All_Columns＆＃34; DataValueField =＆＃34; ALL_COLUMNS＆＃34;属性，DropDownList_SelectedIndexChanged（）保留选定的输入文本。

当前问题： 如果DropDownList提供了DataTextField =＆＃34; All_Columns＆＃34; DataValueField =＆＃34; DATA_TYPE＆＃34;属性，DropDownList_SelectedIndexChanged（）不保留基于所选输入的文本。但它保留了满足索引中相应DATA_TYPE的项列表中的第一个值。

需要解决方案： 如何根据DATA_TYPE属性保留选定的输入文本？我尝试存储Session [＆＃34; DDLValue＆＃34;] = DropDownList.SelectedItem.Text，但它始终保留满足索引中相应DATA_TYPE的项目列表中的第一个值。

即。如果我选择＆＃34; e＆＃34;从以下DropDownList输入中，DropDownList中保留的值为**＆＃34; d＆＃34;

如何保留＆＃34; e＆＃34;即选择带有DATA_TYPE属性的文本。**

COLUMN_NAME  DATA_TYPE  
a            decimal
b            decimal
c            decimal
d            int
e            int
f            varchar
g            varchar  
h            varchar
i            varchar
j            varchar

我的aspx代码：

<asp:DropDownList ID="DropDownList5" runat="server" DataSourceID="SqlDatasource1" DataTextField="All_Columns" DataValueField="DATA_TYPE" OnSelectedIndexChanged ="DropDownList5_SelectedIndexChanged"  AutoPostBack="true">
            </asp:DropDownList>

<asp:SqlDataSource ID="SqlDatasource1" runat="server" ConnectionString="<%$ ConnectionStrings:MyDatabaseConnectionString %>" SelectCommand="SELECT COLUMN_NAME AS 'All_Columns', DATA_TYPE FROM INFORMATION_SCHEMA.COLUMNS WHERE (TABLE_NAME = 'MyTable')">
            </asp:SqlDataSource>

C＃代码：

protected void DropDownList5_SelectedIndexChanged(object sender, EventArgs e)
     {
         Session["DDLValue"] = DropDownList5.SelectedValue;
         /***Retains wrong text***/
     }

Answer 1

试试这个..

如果您在pageload中绑定下拉列表，那么..

 protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
             DropDownList5.DataSource = SqlDatasource1;
             DropDownList5.DataTextField = "All_Columns";
             DropDownList5.DataValueField = "DATA_TYPE";
             DropDownList5.DataBind();
        }
    }

<强>标记：

<asp:ScriptManager runat="server" ID="ScriptManager1" EnablePageMethods="true"></asp:ScriptManager>

<asp:DropDownList ID="DropDownList5" runat="server" DataSourceID="SqlDatasource1" DataTextField="All_Columns" DataValueField="DATA_TYPE" OnSelectedIndexChanged ="DropDownList5_SelectedIndexChanged"  AutoPostBack="false" onChange=" abc();">
            </asp:DropDownList>

<强>使用Javascript：

function abc() {
     var ddl = document.getElementById('DropDownList5');
     var datatype= ddl.options[ddl.selectedIndex].value;
     if(datatype=="int")
     {
       PageMethods.createdynamiccontrols_int();
     }  
}

C＃代码：

[System.Web.Services.WebMethod]
     protected void createdynamiccontrols_int()
     {
        //My Logic continues

     }

Answer 2

试试这可能会对你有所帮助

Session [“DDLValue”] = DropDownList5.SelectedItem.Value;

或

Session [“DDLValue”] = Request.Form [DropDownList5.UniqueID] .ToString（）;

Answer 3

正确解决方案：

如果从以下DropDownList输入中选择＆＃34; e＆＃34; ，DropDownList中保留的值为＆＃34; e＆＃34;

COLUMN_NAME  DATA_TYPE  
a            decimal
b            decimal
c            decimal
d            int
e            int
f            varchar
g            varchar  
h            varchar
i            varchar
j            varchar

来源：DropDownList with repeated data value fields OnSelected get confused and chooses the first one why?

Aspx代码：

<asp:DropDownList ID="DropDownList5" runat="server"  AutoPostBack="true" OnSelectedIndexChanged ="DropDownList5_SelectedIndexChanged" DataSourceID="column_list_for_filter">
</asp:DropDownList>                           

<asp:SqlDataSource ID="column_list_for_filter" runat="server">
</asp:SqlDataSource>

C＃代码：

protected void Page_Load(object sender, EventArgs e)
    {      
        if (!IsPostBack)
        {
            BindDropDownLists();
        }

        else
        {
            if (!String.IsNullOrEmpty(DropDownList5.SelectedValue))
            {
                if (DropDownList5.SelectedValue.Contains("decimal"))
                {
                    createdynamiccontrols_decimal();
                }

                else if (DropDownList5.SelectedValue.Contains("varchar"))
                {
                    createdynamiccontrols_varchar();
                }
                else if (DropDownList5.SelectedValue.Contains("datetime"))
                {
                    create_cntrls();
                }

                else if (DropDownList5.SelectedValue.Contains("int"))
                {
                    Create();
                }


            }

        }
    }

private void BindDropDownLists()
     {
         column_list_for_filter.ConnectionString = connection;
         column_list_for_filter.SelectCommand = "SELECT DATA_TYPE + '_' + convert(varchar(10), ROW_NUMBER() OVER(ORDER BY DATA_TYPE))as DATA_TYPE, COLUMN_NAME FROM INFORMATION_SCHEMA.COLUMNS WHERE (TABLE_NAME = 'RESULT' AND COLUMN_NAME IN ('a','b','c','d','e','f','g','h','i'))";
         DropDownList5.DataTextField = "COLUMN_NAME";
         DropDownList5.DataValueField = "DATA_TYPE";
         DropDownList5.DataBind();

     }

DropDownList保留错误的输入文本，而不是其List of Items中的选定输入

3 个答案: